Coil form and the like



Dec. 29, 1942. w w. F. STAHL COIL FORM AND THE- LIKE Filed llarch 7, 1941 v jizaerziwt' E/zmfdfaZ z, \w M the core.

Patented Dec. 29, 1942 STATES PATET FHCE 2,306,907 con. r-omvr AND 'rna LIKE William F. Stahl, Evanston, n1. Application March '1, 1941, Serial No. 382,130

3 Claims.

This invention relates to a coil form and the like. It is particularly useful as a bobbin or spool for coil windings or other windings, and obviously will be applicable to other uses.

An object of the invention is to provide a small and inexpensive structure which is extremely Figure 1 is a perspective view of a spool or bobbin embodying my invention; Fig. 2, a perspective view of the core employed; Fig. 3, a perspective view of one of the flanges used; Fig. 4, an enlarged longitudinal sectional view, the section being taken as indicated at line 4 of Fig. 1; Fig. 5, an end view of a modified form of structure; Fig. 6, an end view of-one of the flanges employed; Fig. 'l, a perspective view of the core; and Fig. 8, a broken part sectional view, the section being taken as indicated at line 8 of Fig. 5.

In the form of the invention illustrated in Figures 1 to 4 inclusive, Ill designates a core which may be formed of any suitable material in any desired manner. Such a core may be formed by winding adhesive tape around a mandrel of square, round or other shape to form a break or form weakening fissures. Whereas. if

the end portions of the core were uninterrupted.

they would be annular in form and any attempt to swage such portions outwardly would increase the diameter thereof and tend to break or tearthe material, with the present construction the end portions, being interrupted are semi-circular and are not subject to this diiflculty.

After the structure has been formed with the flanges secured by means of the riml5, I imme'rse the entire form in a solution of a hardening varnish, lacquer, or condensation product, such as phenol formaldehyde solution. The layer of varnish or hard material penetrates the rim and also the slot spaces andyupon hardening, permanently locks the rim in posit.on and also the tongues l4 within the slots ii. If paper is employed, as is customary, the hardening solu tion causes the tongues M to become rigid members and the rims lfi'to become rigid shoulders.

When the wire or other winding is wound upon the central core portion, pressure is exerted outwardly against the flanges 42, and it will be noted that pressure against the flanges is sustained by the rims l5 and the tongues M. The

tongues M, on their inner faces, bear against the ends of. the core and thus the flange is locked between the rim and the core. Any tendency for the flanges to swing outwardly away from each other at their outer peripheries upon the fulcrum provided by the rims is prevented by the engagement of the tongues against the end.

' Further, the tongues prevent any tendency of core of the desired shape. The ends of the core are provided with notches or recesses H for a purpose which will be later described.

The end flange l2 may be formed of paper, fiber, Bakelite, or any other suitable material. The flange is provided with a central opening it and with integral tongues l4 which project into the opening l3.

In the assembly operation, the flanges ii are 4 inserted over the core ends, and the tongues ll are brought into engagement with the slots ll of This leaves a forward portion of each core end projecting beyond the flange ii. The ends are then swaged outwardly and rearwardly to form locking rims l5 bearing against the flanges l2. By interrupting the end portions of the core with slots H, it is found that the core can be turned smoothly anduniformiy into contact with the flanges l2 without tendency to the flanges to rotate during the winding operatiun.

The entire operation is simple and as a result of it, an extremely sturdy spool is provided, even though formed of fragile material, such as paper or tape.

In the modified form of structure shown in Figures 5 to 8, the core I8 is provided with four slots H, a projecting lip l8 being provided between each of the slots. The end flange I9 is provided with four curved slots 20 adapted to receive the lips I. In the assembled structure illustrated in Figures 5 to 8, the lips l8 are turned either toward or away fromthe axis of the spool orcore to form locking rims against the end flange l9. In the illustration given, the lips are turned toward the axis and inwardly with respect to the center of the spool. After the swaging back of the portions I8, the hardening solution or material is brought into contact with the parts to saturate them and set them in their assembled position. The solution anchors the lips v ,hardening material.

l8 flrmly within 'the slots and the rim portions rigidly against the flanges It.

It will be understood that the hardening material is used with a paper or soft core and would not be used with a core formed of hard material.

Usually the core i8 is formed by winding gummed tape, forming a series of laminations.

The swaging of the ends serves to break the laminations and provides recesses to receive the Thus, after the dipping operation, the assembled spool or bobbin is permanently secured in the position shown upon the during the swaging operation. Further, the open-.

ings serve as means for locking the tongues therein when the hardening solution is applied.

While in the foregoing specification, I have i set forth certain details and steps as illustrative of the method and product, it will be understood that, wide variation therein may be made without departing from the spirit of my invention.

I claim: I

1. A form for windings and the like, comprising a tubular core having short longitudinallyextending slots in opposed portions of one of the ends thereof, and a flange mounted at said end of said core in a planetransverse to the axis of the core, said flange having a central opening receiving the core and having radial tongues extending inwardly from the periphery of said central opening received within said slots, each of said tongues being of a length substantially the same as the thickness of the wall of the core and being in en'gagement with the wall of the core at the base of the longitudinal slot within which the tongue is received, said end portion of the core extending beyond the flange and being struck outwardly and rearwardly to form a locking rim in engagement with the flange.

the core and being in engagement with the wall of the core at the base of the longitudinal slot within which the tongue is received, the end portions of the core extending beyond the flanges and being struck outwardly and rearwardly to form locking rims in engagement with the flanges.

3. A form for windings and the like, comprising a laminated tubular paper core having short longitudinally-extending slots in opposed portions of each of the ends thereof, and a flange mounted at each end of said core in a plane transverse to the axis of the come, said flange having a central opening receiving the core and having radial tongues extending inwardly from the,

periphery of said central opening received within said slots, each of said tongues being of a length substantially the same as the thickness of the wall of the core and being in engagement with the wall of the core at the base of the longitudinal slot within which the tongue is received, the endportions of the core extending beyond the flanges and being struck outwardly and rearwardly to separate the laminations of, the end portions thereof and toform locking rims in engagement with the flanges, and a hard material within the space between the separated laminations of said end portions of the core and adhering thereto to maintain said end portions in rearwardly-turned position, said hard material adhering also to the flanges and the radial tongues thereof.

1 WILLIAM F. STAHL. 

